slow cooker osso bucco This slow cooker osso bucco is deliciously simple and convenient crock pot meal. Serves 6 plain flour 6 osso bucco salt and pepper 2 carrots 2 onions 3 celery sticks 4 cloves garlic 4 tbs tomato paste 400g tin diced tomatoes 1 cup white wine 2 beef stock cubes 1 bay leaf 2 cups water.